|  | 4.4 | Explain Layer 2 Design
| 4.4.5 | Determining the size of collision domains in hubbed and switched networks
To determine the size of a collision domain, you must determine how many hosts are physically connected to any single port on the switch. This also affects how much network bandwidth is available to any host. In an ideal situation, there is only one host connected on a LAN switch port. This would make the size of the collision domain 2 (the source host and destination host). Because of this small collision domain, there should be almost no collisions when any two hosts are communicating with each other. Another way to implement LAN switching is to install shared LAN hubs on the switch ports and connect multiple hosts to a single switch port. All hosts connected to the shared LAN hub share the same collision domain and bandwidth. Note that some older switches, such as the Catalyst 1700, don't truly support sharing the same collision domain and bandwidth because they don't maintain multiple MAC addresses mapped to each port. In that case, there are many broadcasts and ARP requests.